Two Weird Warblers

A pair of apparent hybrid warblers on opposite sides of the continent have been making the rounds on various listservs and forums over the last week. Both have relatively mysterious parentage and offer few outward clues as to their genetic ancestry. In any case, short of the unlikely and unnecessary action of drawing blood for a full workup there’s little certainty here, but skilled birders can still make some well-informed and fun guesses.

The most bizarre of the two has to be a male Dendroica…er… Setophaga type warbler present for a few days at Summer Lake in south-central Oregon. At first glance it suggests a strange colored Canada Warbler, a popular guess for one of the parents. Suggestions for the other half include Black-throated Blue, American Redstart and either of the Mourning or MacGillivray’s duo. It certainly doesn’t appear similar to any known hybrids, and it looks to me to be not far off the Junkin’s Warbler – a bird that was determined to be Kentucky x Mourning, a cross no one expected – discovered in western New York several years ago. Odd indeed.

The second bird comes from Falmouth, Massachusetts. It’s a female with slightly less confused parentage, as it has been narrowed down to three possibilities, Prairie, Blue-winged, and Pine. Photos can be found here. The Prairie influence looks to me to be pretty strong, but the other is anyone’s guess.

Both are fascinating birds, even if they’re not ending up a list anytime soon. Anyone up for taking a crack at either of these birds? No guess is too weird. If we learned anything from the aforementioned Junkin’s Warbler, it’s that the outlandish is almost as reasonable as the expected.

Nate Swick

Nate Swick is the editor of the American Birding Association Blog. A long-time member of the bird blogosphere, Nate has been writing about birds and birding at The Drinking Bird since 2007, but can also be found writing regularly at 10,000 Birds.
In the non-digital world, he's an environmental educator and interpretive naturalist. Nate lives in Greensboro, North Carolina, with his wife, Danielle, and two young children, who are not yet aware that they are being groomed to be birders.

In the photo above, the looks very similar to a Canada Warbler, but then in this photo, the Kentucky influence looks pretty strong since there is a strong black mustachial marking. I’m not sure if the other suggested parents would produce that.

I hope someone catches these two birds for DNA testing!

Sean Fitzgerald

I agree that CAWA x MOWA seems to fit well (especially in light of the additional image linked from John’s comment above). An awesome looking bird!

Sean Fitzgerald

And KEWA x CAWA/MOWA seems equally plausible…

http://www.surfbirds.com/blog/northcoastdiaries/ Mike Patterson

In sorting out likely parents, it’s important to take the rarity of pure individuals in to account. Most of these pairing are rare to start with add rareness of pure individuals and things become even less probable. There are only 4 accepted records of Kentucky Warbler for Oregon, 5 for Mourning Warbler and 7 for Canada Warbler. Black-throated Blue Warbler is a nearly annual vagrant. American Redstart is a breeder with a very localized distribution. MacGillivray’s Warbler is the most common of the parental choices and has a distribution that covers most of the state. Nashville Warbler is another species that came up in the discussions and I still think its a good candidate. At any rate, I favor a pairing of Oregon-common species. I like NashXBlkthblue…

Short of collecting DNA samples, many of these discussion are mostly just somebody’s opinion, though.

It’s been a year of unusual hybrid warblers in the Pacific Northwest. I photographed a HermitXsomething hybrid back in May. The default is HermitXTownsend’s, but this bird fits the much rarer HExBlack-throated Gray combination better.

And another likely hybrid was found at Field Oasis about 40 miles south of Malheur National Wildlife refuge that some still insist is really a genuine Black-throated Green, but is more probably a HermitxTownsend’s back cross.

Nashville definitely seems a good bet for one of the parents. Like you, I would certainly expect a common breeder as opposed to something more rare.

The more I consider it, I think Nashville x BT Blue or Nasville x MacGillivray’s is the most likely option.

http://seagullsteve.blogspot.com/ Seagullsteve

At first glance, without looking at where it was photographed, I thought Canada X Black-throated Blue. I still see that more than anything else, despite the location. When considering hybrids I think its important to remember that the underparts are almost all white (although there is some dingy yellow in there?), which would seemingly rule out crosses of 2 different yellow-bellied species (Nash X Mac, Canada X Mourning/Mac, Nash X Kentucky, etc). Cool bird!

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